{"id":"CVE-2026-74268","state":"PUBLISHED","title":"tcp: clear sock_ops cb flags before force-closing a child socket","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: clear sock_ops cb flags before force-closing a child socket\n\nA child socket inherits the listener's bpf_sock_ops_cb_flags via\nsk_clone_lock(). If its setup fails in tcp_v4_syn_recv_sock() /\ntcp_v6_syn_recv_sock(), the child is freed through put_and_exit, where\ninet_csk_prepare_forced_close() drops the socket lock and tcp_done() runs\nwithout it.\n\nIf BPF_SOCK_OPS_STATE_CB_FLAG was inherited, tcp_done() -> tcp_set_state()\ncalls tcp_call_bpf(), which expects the lock and trips sock_owned_by_me():\n\n  WARNING: include/net/sock.h:1799 at tcp_set_state+0x433/0x550\n  RIP: 0010:tcp_set_state+0x433/0x550 include/net/sock.h:1799\n  Call Trace:\n   <IRQ>\n   tcp_done+0xba/0x250 net/ipv4/tcp.c:5095\n   tcp_v4_syn_recv_sock+0x850/0xa50 net/ipv4/tcp_ipv4.c:1787\n   tcp_check_req+0xf30/0x1360 net/ipv4/tcp_minisocks.c:926\n   tcp_v4_rcv+0x1047/0x1b50 net/ipv4/tcp_ipv4.c:2164\n   </IRQ>\n\nThe child is freed before it is ever established, so it should run no\nsock_ops callback. Clear its cb flags in inet_csk_prepare_for_destroy_sock(),\nthe common point for the IPv4, IPv6 and chtls forced-close paths and for the\nMPTCP ->syn_recv_sock() failure path (dispose_child), which reaches tcp_done()\non a child that was never established too.","publishedAt":"2026-08-15T05:57:42.920Z","updatedAt":"2026-10-16T18:55:28.993Z","severity":{"score":9.8,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d44874910a26f3a8f81edf873a2473363f07f660","status":"affected","lessThan":"5d5389b2c37ca00da61d1407618ebe15abae0c8b","versionType":"git"},{"version":"d44874910a26f3a8f81edf873a2473363f07f660","status":"affected","lessThan":"9f30ba9aa0270a18fdd1e6cd426c480c35f7de9d","versionType":"git"},{"version":"d44874910a26f3a8f81edf873a2473363f07f660","status":"affected","lessThan":"71e9c53220abd7f5a45aa4d5e5b420d3479f3a4f","versionType":"git"},{"version":"d44874910a26f3a8f81edf873a2473363f07f660","status":"affected","lessThan":"9fffa6465851a1910a6e9cb7272787dd615b26b1","versionType":"git"},{"version":"d44874910a26f3a8f81edf873a2473363f07f660","status":"affected","lessThan":"fe23d56e9266d58ba5c380f1970118eedeee0b68","versionType":"git"},{"version":"d44874910a26f3a8f81edf873a2473363f07f660","status":"affected","lessThan":"ce311bd2e36596f0aa2c92ca86fb3e019ac57eae","versionType":"git"},{"version":"d44874910a26f3a8f81edf873a2473363f07f660","status":"affected","lessThan":"8874dafc9099bc49c2e5ebba030f85d276421f92","versionType":"git"},{"version":"d44874910a26f3a8f81edf873a2473363f07f660","status":"affected","lessThan":"990348e5bb457697c2f1f7f7b65154a3334d9d2b","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/net/tcp.h","net/ipv4/inet_connection_sock.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.16","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.16","versionType":"semver"},{"version":"5.10.270","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.221","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.188","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.157","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.110","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/net/tcp.h","net/ipv4/inet_connection_sock.c"]}],"references":["https://git.kernel.org/stable/c/5d5389b2c37ca00da61d1407618ebe15abae0c8b","https://git.kernel.org/stable/c/9f30ba9aa0270a18fdd1e6cd426c480c35f7de9d","https://git.kernel.org/stable/c/71e9c53220abd7f5a45aa4d5e5b420d3479f3a4f","https://git.kernel.org/stable/c/9fffa6465851a1910a6e9cb7272787dd615b26b1","https://git.kernel.org/stable/c/fe23d56e9266d58ba5c380f1970118eedeee0b68","https://git.kernel.org/stable/c/ce311bd2e36596f0aa2c92ca86fb3e019ac57eae","https://git.kernel.org/stable/c/8874dafc9099bc49c2e5ebba030f85d276421f92","https://git.kernel.org/stable/c/990348e5bb457697c2f1f7f7b65154a3334d9d2b"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/74xxx/CVE-2026-74268.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-74268","state":"PUBLISHED","datePublished":"2026-08-15T05:57:42.920Z","dateUpdated":"2026-10-16T18:55:28.993Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-15T05:44:03.878Z"},"containers":{"cna":{"title":"tcp: clear sock_ops cb flags before force-closing a child socket","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: clear sock_ops cb flags before force-closing a child socket\n\nA child socket inherits the listener's bpf_sock_ops_cb_flags via\nsk_clone_lock(). If its setup fails in tcp_v4_syn_recv_sock() /\ntcp_v6_syn_recv_sock(), the child is freed through put_and_exit, where\ninet_csk_prepare_forced_close() drops the socket lock and tcp_done() runs\nwithout it.\n\nIf BPF_SOCK_OPS_STATE_CB_FLAG was inherited, tcp_done() -> tcp_set_state()\ncalls tcp_call_bpf(), which expects the lock and trips sock_owned_by_me():\n\n  WARNING: include/net/sock.h:1799 at tcp_set_state+0x433/0x550\n  RIP: 0010:tcp_set_state+0x433/0x550 include/net/sock.h:1799\n  Call Trace:\n   <IRQ>\n   tcp_done+0xba/0x250 net/ipv4/tcp.c:5095\n   tcp_v4_syn_recv_sock+0x850/0xa50 net/ipv4/tcp_ipv4.c:1787\n   tcp_check_req+0xf30/0x1360 net/ipv4/tcp_minisocks.c:926\n   tcp_v4_rcv+0x1047/0x1b50 net/ipv4/tcp_ipv4.c:2164\n   </IRQ>\n\nThe child is freed before it is ever established, so it should run no\nsock_ops callback. Clear its cb flags in inet_csk_prepare_for_destroy_sock(),\nthe common point for the IPv4, IPv6 and chtls forced-close paths and for the\nMPTCP ->syn_recv_sock() failure path (dispose_child), which reaches tcp_done()\non a child that was never established too."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d44874910a26f3a8f81edf873a2473363f07f660","status":"affected","lessThan":"5d5389b2c37ca00da61d1407618ebe15abae0c8b","versionType":"git"},{"version":"d44874910a26f3a8f81edf873a2473363f07f660","status":"affected","lessThan":"9f30ba9aa0270a18fdd1e6cd426c480c35f7de9d","versionType":"git"},{"version":"d44874910a26f3a8f81edf873a2473363f07f660","status":"affected","lessThan":"71e9c53220abd7f5a45aa4d5e5b420d3479f3a4f","versionType":"git"},{"version":"d44874910a26f3a8f81edf873a2473363f07f660","status":"affected","lessThan":"9fffa6465851a1910a6e9cb7272787dd615b26b1","versionType":"git"},{"version":"d44874910a26f3a8f81edf873a2473363f07f660","status":"affected","lessThan":"fe23d56e9266d58ba5c380f1970118eedeee0b68","versionType":"git"},{"version":"d44874910a26f3a8f81edf873a2473363f07f660","status":"affected","lessThan":"ce311bd2e36596f0aa2c92ca86fb3e019ac57eae","versionType":"git"},{"version":"d44874910a26f3a8f81edf873a2473363f07f660","status":"affected","lessThan":"8874dafc9099bc49c2e5ebba030f85d276421f92","versionType":"git"},{"version":"d44874910a26f3a8f81edf873a2473363f07f660","status":"affected","lessThan":"990348e5bb457697c2f1f7f7b65154a3334d9d2b","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/net/tcp.h","net/ipv4/inet_connection_sock.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.16","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.16","versionType":"semver"},{"version":"5.10.270","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.221","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.188","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.157","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.110","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/net/tcp.h","net/ipv4/inet_connection_sock.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/5d5389b2c37ca00da61d1407618ebe15abae0c8b"},{"url":"https://git.kernel.org/stable/c/9f30ba9aa0270a18fdd1e6cd426c480c35f7de9d"},{"url":"https://git.kernel.org/stable/c/71e9c53220abd7f5a45aa4d5e5b420d3479f3a4f"},{"url":"https://git.kernel.org/stable/c/9fffa6465851a1910a6e9cb7272787dd615b26b1"},{"url":"https://git.kernel.org/stable/c/fe23d56e9266d58ba5c380f1970118eedeee0b68"},{"url":"https://git.kernel.org/stable/c/ce311bd2e36596f0aa2c92ca86fb3e019ac57eae"},{"url":"https://git.kernel.org/stable/c/8874dafc9099bc49c2e5ebba030f85d276421f92"},{"url":"https://git.kernel.org/stable/c/990348e5bb457697c2f1f7f7b65154a3334d9d2b"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":9.8,"baseSeverity":"CRITICAL"},"scenarios":[{"lang":"en","value":"AV:N - Remote attackers reach inet_csk_prepare_for_forced_close() via the standard TCP input path (tcp_v4_rcv/tcp_v6_rcv → tcp_check_req → tcp_v4/v6_syn_recv_sock put_and_exit) while processing attacker-sent handshake packets in softirq, with no local access required.\nAC:L - Attackers control handshake completion and can repeatedly force child setup failures—e.g., MPTCP JOIN/sport-mismatch dispose_child paths, ENOMEM under connection pressure in __inet_inherit_port or MD5/AO copy, or chtls setup failure—making put_and_exit reachable without conditions outside their influence.\nPR:N - The receive path is pre-authentication TCP/MPTCP processing; no victim credentials or capabilities are required. Exploitation only needs network reachability to a listener whose admin already attached cgroup BPF sock_ops setting BPF_SOCK_OPS_STATE_CB_FLAG (common on Kubernetes/Cilium/cloud nodes).\nUI:N - No victim interaction is needed beyond normal exposure of a TCP listener; the attacker triggers the bug entirely by sending network packets that complete then fail child socket creation.\nS:U - Vulnerability impact stays within the kernel on the host receiving the traffic; it does not cross VM, container runtime, or IOMMU security boundaries and represents standard in-kernel memory/lock safety impact.\nC:H - Inherited BPF_SOCK_OPS_STATE_CB_FLAG causes tcp_call_bpf() to run on an unlocked, partially torn-down child socket; BPF helpers can read tcp_sock fields without proper locking, enabling unsynchronized kernel memory reads that could disclose sensitive data.\nI:H - tcp_call_bpf() marks is_locked_tcp_sock while the socket lock was dropped, allowing cgroup BPF sock_ops programs to call bpf_setsockopt and modify tcp_sock/kernel state during forced close, creating plausible memory corruption and control-flow compromise primitives.\nA:H - sock_owned_by_me() WARN fires on this path and concurrent BPF access during tcp_done()/inet_csk_destroy_sock() can cause kernel oops or panic; remote attackers can repeatedly trigger the softirq failure path for denial of service on internet-facing BPF-enabled servers."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-09-14T11:58:42.864Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.16","versionEndExcluding":"5.10.270"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.16","versionEndExcluding":"5.15.221"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.16","versionEndExcluding":"6.1.188"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.16","versionEndExcluding":"6.6.157"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.16","versionEndExcluding":"6.12.110"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.16","versionEndExcluding":"6.18.40"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.16","versionEndExcluding":"7.1.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.16","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-74268","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T18:51:48.226503Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-16T18:55:28.993Z"}}]}}}